Recently, compact electronics cameras have become widely used, and capturing images have become easier than ever before. The handiness has encouraged more users to take electronics cameras with themselves and capture an image in a room and at night, as well as outside in the daytime. Since it is bright outside in the daytime, an image can be captured at a fast shutter speed even in automatic capturing. Besides, the brightness in the day time makes possible eliminating the need for unnecessarily high photographic sensitivity. This allows an image having little blurring and noise to be captured.
Due to short of brightness, meanwhile, capturing in a room and at night needs to employ a slow shutter speed to obtain a large amount of light, or to increase photographic sensitivity. The slow shutter speed, however, causes a problem in that the image blurs in the case where the object or the electronics camera moves while the shutter is opening. The high photographic sensitivity causes a problem in that a lot of noise is developed on the image even though the image is less blurred.
One of solutions to the problems is a capturing method to use a flash unit. When photographing an object at a short distance, using a flash unit makes possible enjoying brightness as good as that of outside in the daytime. Thus, the user can capture an image having little blurring and noise.
The most appropriate setting of an operating condition of the flash unit, however, cannot be determined until the user actually photographs the object to see the result. Since it is difficult to re-capture an image in the case where an opportunity for capturing an image is limited; for example the case of asking somebody to take a picture during a trip, and the case where an environment for capturing changes from moment to moment, the user desirably obtains a capturing result with no fault at the first try.
A technique described in Patent Reference 1 proposes, for example, a method for preventing a failure in photographing involving a use of a flash unit by changing a setting of a light intensity parameter of the flash or a setting of an ISO sensitivity to capture images in various kinds of brightness. This can prevent the user from failing to capture an image both at night and in the daytime.
Further, a technique described in Patent Reference 2 proposes, for example, a method for controlling an amount of light from the flash unit by de-actuating the flash when reflected flash arrives at a light receiving unit. Since this makes possible providing an appropriate amount of flash according to a distance to the object, the user can capture an image having little blurring and noise.